NEWS

Hormone therapy helps prevent recurrent premature birth

By LESLIE H. LANG
UNC School Of Medicine

CHAPEL HILL -- Injections of a progesterone hormone drug given to pregnant women whose previous babies had been born prematurely can help prevent another pre-term birth, new research shows.

Researchers from the University of North Carolina at Chapel Hill participated in a multi-center study of the drug 17-alpha-hydroxyprogesterone caproate, also known as 17P. Small studies from the 1970s and 1980s suggested that the therapy might prevent recurrent pre-term births, but this is the first large-scale rigorous trial to confirm that it could, according to Dr. John M. Thorp Jr., McAllister distinguished professor of obstetrics and gynecology at UNC’s School of Medicine and principal investigator at the UNC study site.

"I believe this is the first primary prevention tool to actually prevent pre-term delivery that’s ever been rigorously proven to work," he said.

The new findings will be presented Thursday (Feb. 6) at the 23^rd Annual Meeting of the Society for Maternal-Fetal Medicine, held in San Francisco.

Participants in the study included more than 450 pregnant women with a well-documented history of spontaneously giving birth prior to 37 weeks. Of these women, whose pregnancies were 16 to 20 weeks along, 306 were randomly assigned to treatment with weekly injections of 17P, while 153 received placebo injections and served as a control group. Injections continued until 36 weeks gestation. The study was double-blinded; neither researchers nor participants knew to which of the groups participants were assigned.

Treatment with 17P significantly reduced the risk of pre-term birth at less than 37, 35 and 32 weeks gestation. The race of participants was not a factor in treatment success.

The risk of pre-term term birth prior to 37 weeks was reduced by 34 percent, and the risk for delivery at less than 32 weeks was reduced by 42 percent.

"In fact, the study was stopped by such a dramatic and positive effect of treatment," Thorp said.

Babies who are born at less than 32 weeks are most at risk, in terms of health problems and mortality. That’s why the study indicates that therapy with 17P would have a great impact on nursery statistics, particularly neonatal intensive care units, said Dr. Kenneth J. Moise Jr., professor of obstetrics and gynecology and division chief of maternal and fetal medicine at UNC.

"Do you save days in the nursery? Do you save bad outcomes? This is the first study to have done that," he said.

The progesterone drug is not new. It is approved by the U.S. Food and Drug Administration and saw extensive use in the 1950s and 1960s as a synthetic progestin.

The study involved 19 members of the Maternal Fetal Medicine Units Network of the National Institute of Child Health and Human Disease at the National Institutes of Health.

The UNC trial was a collaborative effort of the departments of obstetrics and gynecology, and pediatrics; the Maternal Infant Health Center; and the Cecil G. Sheps Center for Health Services Research.

UNC will be involved in another clinical trial also planned for women at risk for pre-term birth, Thorp said. In this study, all women will be treated with 17P and randomized to receive either an omega-3 fatty acid or placebo pill. Studies have linked omega-3 fatty acids (associated with cold-water fish and some other food sources) with increased gestational length.

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Note: Contact Thorp at (919) 966-1601 or thorp@med.unc.edu

School of Medicine contact: Les Lang, (919) 843-9687 or llang@med.unc.edu